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An unusually shaped party cup next to a regular cup.

Party Cup

Which cup holds more liquid?

Geometry, 8th

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A worksheet on a desk with many possible similar triangles.

Similarity Scanner

Which numbered triangle(s) will receive a check mark?

Geometry, 8th

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A map view of a bridge going across a body of water.

Bumps on a Bridge

How many bumps are on the entire bridge?

5th

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A 3D landscape view of a water treatment facility.

Water Leak

Will service arrive before the tank runs out of water?

Calculus

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A line of dominoes stacked in a row ready to be tipped over.

Dominoes

How long will it take to knock down all the dominoes?

6th

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The moon rising over a hill.

Moon Rise

How long will it take the moon to rise?

Geometry, 7th

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A car at the top of a ramp.

Car Ramp

How far did the car travel on the final ramp?

Algebra 1, Geometry

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A phone timer.

Timer

How much time is left?

7th

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A phone calculator.

Calculator Countdown

How many times was the same number subtracted from 104 to get to 5?

3rd

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A satellite view of Apple's headquarters.

Apple Park

How long would it take the average person to walk around the entire building?

7th

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A screenshot from America Ninja Warrior. A contest is about to grab onto the Captain's Wheel.

Captain’s Wheel

How many degrees did he have to turn the wheel?

Geometry

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A satellite view of lava taking over a field.

Lava Field

How long will it take for the lava to cover the field?

Geometry

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Showing 12 of 75 tasks

75

free tasks • Grades 3–12

3 Act Math

A growing library of free, curiosity-driven math tasks. Each lesson opens with a single perplexing question—then students build the math to answer it. No worksheets to start, just a moment that makes a whole class lean in.

Always free

Starts with a question

Grades 3–12

The structure

What Is 3 Act Math?

3 Act Math is a way of teaching a math problem as a story in three acts. Instead of handing students a word problem, you show them something puzzling, let them decide what they need to know, and reveal the answer at the end. It turns “do this problem” into “I need to find this out.”

1

The hook

A Question Worth Asking

A short video or image of something surprising. Students notice, wonder, and commit to one question—before a single number appears.

Notice & wonder · estimate

2

the information

Gather What You Need

Students decide what information would actually help, ask for it, and choose a strategy. The math shows up because they sent for it.

Model · calculate · reason

3

the reveal

Show, Don’t Tell

The real answer is revealed, not announced. Students compare it to their estimate—and the gap is what makes them want the “why.”

Compare · justify · extend

Showing 12 of 75 tasks

Filter by Grade

For teachers

Unlocking Curiosity

The tasks above are the spark. The Unlocking Curiosity Workshop is how you turn that spark into a way of teaching—every day, in every lesson.

Go deep on 3 Act Math, learn how to manufacture curiosity in ordinary topics, and get the learning strategies and classroom setup that make students want to think.

Self-paced • For K–12 teachers

What you’ll learn

Plan, launch, and facilitate tasks that land—from the opening hook to the reveal.

Turn ordinary textbook problems, vocabulary, and worksheets into questions students actually want to answer.

Put the 5 Practices for orchestrating productive mathematics discussions to work so every student's thinking moves the lesson forward.

Engaging practice strategies, estimation challenges, and more ways to make repetition feel worth doing.

Good Questions

3 Act Math Questions

  • A 3 Act Math task teaches a problem as a story in three acts. Act 1 is a short, perplexing video or image that prompts a single question. Act 2 is where students decide what information they need and do the math. Act 3 reveals the real answer so students can compare it to their estimate. It replaces a dry word problem with a reason to care about the answer.

  • Our 3 Act Math library spans grades 3–12. Use the grade filter to narrow to any individual grade—pick one or several. Many tasks work across more than one grade depending on the strategies you allow, so they’ll show up under each grade they fit.

  • Yes. Every task in this catalog is free to use in your classroom or at home—no login required to start. A free trial of When Math Happens unlocks the full Parent and Student courses, the Unlocking Curiosity Workshop, and the Standards-Based Grading Workshop.

  • Play Act 1 with no setup and ask students what they notice and wonder. Then pose the question and have everyone estimate—including a guess that's too high and one that's too low. In Act 2, ask what information they need to solve it, then give it to them. Reveal Act 3, compare it to the estimates, and discuss why the math worked. The Unlocking Curiosity Workshop covers this facilitation in depth.

  • The three-act structure for math tasks was popularized by math educator Dan Meyer. When Math Happens builds original tasks in that spirit—curiosity first, math second—and pairs them with strategies for using them well.

  • It is a self-paced workshop for K–12 teachers that goes beyond the tasks: how to facilitate 3 Act Math, how to spark curiosity in everyday lessons, the learning strategies behind it, and how to set up a classroom where students want to think.

  • The library grows regularly. There are 70+ tasks today, with more added over time—bookmark this page and check back, or subscribe to our newsletter to be notified when new ones launch.

Pick a Task and Make a Class Lean In

Start with one perplexing question today—then learn how to make every lesson feel that way with the Unlocking Curiosity Workshop.

Free for 7 days • Cancel anytime

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